Apparatus for casting stereotype plates



Feb. 22, 1938. G w N 2,109,206

APPARATUS FOR CASTING STEREOTYPE PLATES Filed June 26, 1935 10 Sheets-$heet l ATTORNEY.

Feb. 22, 1938. e. w. BUNGAY APPARATUS FOR CASTING STEREOTYPE PLATES l0 Sheets-Sheet 2 Filed June 26, 1935 INVENTOR.

ATTORNEY.

Feb. 22, 1938. e. w. BUNGAY 2,109,206

APPARATUS FOR CASTING STEREOTYPE PLATES Filed June 26, 1955 l0 Sheets-Sheet 3 59 7a 58 M 3m I 36% L mm 9 ATTORNEY.

Feb. 22, 1938. e. w. BUNGAY APPARATUS FOR CASTING STEREOTYPE PLATES Filed June 26, 1935 10 Sheets-Sheet 4 INVENTOR.

ATTORNEY.

Feb. 22, 1938. G, w. BUNGAY APPARATUS FOR CASTING STEREOTYPE PLATES Fil ed June 26, 1935 10 Sheets-Sheet 6 ATTORNEY.

Feb. 22, 1938. s. w. BUNGAY APPARATUS FOR CASTING STEREOTYPE PLATES Filed June 26, 1935 4 l0 Sheets-Sheet 7 ATTORNEY.

Feb, 22, 1938. G. w. BUNGAY APPARATUSFOR CASTING STEREOTYPE PLATES Filed June 26, 1935 10 Sheets-Sheet 8 WWO! 54 l I 61' g INVBNTOR.

ATTORNEY.

Feb. 22, 1938. G. w BUNGAY 2,109,206

APPARATUS FOR CAshNe STEREOTYPE PLATES Filed June 26, 1935 M10 Sheets-Sheet 9 ATTORNEY.

Feb. 22, 1938; I G. w. BUNGAY I APPARAT US FOR CASTING STEREOTYPE PLATES.

1o Sheets-Sheet 10 Filed June 26, 1935 I ENTOR.

K ATTORNEY.

Patented Feb. 22, 1938 UNITED STATES APPARATUS FOR CASTING STEREOTYIE' PLATES George W. Bungay, Brooklyn, N. Y., assigncr to Bungaytype-Delaware, Inc., New York, N. Y., a corporation of Delaware Application June .26, 1935, Serial No. 28,439

19 Claims.

This invention relates to the casting of stereotype plates, and more particularly to a method and apparatus for casting stereotype plates suitable for high quality printing.

This application is a continuation in part of my copending application for Method and apparatus for casting stereotype plates, Serial No. 745,550, filed September 26, 1934.

Stereotype plates have heretofore been generally considered unsuitable. for high quality printing for various reasons well known in the printing art. For example, the printing surface may be irregular due to imperfections in the matrix, uneven cooling of the metal, shrinkage of the metal away from the matrix, bulging of the matrix due to expansion, poorly controlled temperatures, etc. Different plates may be of non-uniform size because of unequal expansion of the matrix, non-uniform shrinkage of the metal, differences in casting temperatures, differences in rates of cooling, and, in general/because of the difiiculty in casting two plates under exactly the same conditions.

For these reasons stereotype plates do not possess the definition or registration required for half-tone color printing and quality magazine work, circulars, and the like, and recourse has been had to electrotype plates for this type of printing. Electrotype plates, however, are expensive; they require considerable time for their preparation; and they are generally unsuited for work requiring cheapness and speed.

It is accordingly an object of this invention to render stereotype plates suitable for high quality printing.

Another object is to improve stereotype plates so that they may compete with electrotype plates as to quality of printing.

Another object is to increase the usefulness and availability of stereotype plates.

Another object is to provide a method of casting stereo-type plates having uniform printing surfaces, improved definition and registration, greater depth of printing faces, and, in general, having characteristics suitable for high quality printing.

Another object is to provide a simple, convenient, efficient and dependable apparatus for accomplishing the above purposes.

Another object is to provide a stereotype casting machine of the above type. which is convenient and simple to operate.

The invention also consists in the various new and original features of construction and combinations of parts hereinafter set forth and claimed.

A feature of the invention consists in casting the stereotype plate under a pressure adapted to cause the molten metal to penetrate the various 5 impressions in the matrix and in maintaining the metal in pressure engagement with the matrix while the metal cools to the temperature. at which it is removed from the casting machine.

In one embodiment, this is accomplished by applying mechanical pressure to the molten metal sufficient to compress the metal andto cause the metal to penetrate theimpressionsin the matrix. The edges of the matrix are firmly clamped in position, and, as the metal cools and becomes solidified, fluid pressure is applied to the back surface thereof to hold the printing face firmly against the matrix and to exert sufficient pressure on .the matrix to prevent the same from bulging or otherwise distorting due, for example, to expansion caused by the heat of the molten metal. Hence, the stereotype plate is caused to accurately reproduce the' original printing form both as to size and registration, a feature particularly important, for example, in 425 half-tone color printing where accurate registration of the half-tone dots is essential.

The present invention also provides a simplified means for casting a stereotype plate with a finished printing face. This is accomplished by forming the matrix so that the impressions i therein are held in correct position in the casting box to reproduce the original printing form in the cast plate and in casting under sufiicient pressure to insure penetration of the matrix impressions by the molten metal.

Another feature of the invention consists in the provision of means for maintaining the casting machine at a predetermined temperature during the casting operations. The casting is preferably removed from the machine at an elevated temperature and the cooling is completed. under conditions which prevent warping thereof.

Another feature consists in maintaining trans-' verse pressure on the back of the cast plate to compensate for shrinkage and to maintain the plate in pressure engagement with the matrix while cooling. j f

Another feature consists in casting thestereotype plates under controlled conditions so that .50 the various plates are uniform as to size, definition, registration, etc.

Various other features and advantages will be apparent as the nature of the invention is more fully disclosed Although the various novel features which are believed to be characteristic of this invention will be pointed out in the claims appended hereto, the invention itself, as to its objects and advantages and the manner of its operation, may be better understood by referring to the following description taken in connection with the accompanying drawings illustrating one embodiment thereof.

In the drawings,

Figure 1 is a side elevation of a casting machine constructed in accordance with this invention.

Figure 2 is a front elevation of the machine illustrated in Figure 1.

Figure 3 is a rear elevation thereof, with parts broken away for clearness.

Figure 4.is a top plan View thereof.

Figure 5 is a vertical section taken on the line 55 of Figure 2.

Figure 6 is a horizontal section taken on the line 66 of Figure 2, with the spring handle shown in section.

Figure '7 is a horizontal section similar to Figure 6 but with the mold in open position.

Figure 8 is a front elevation of the slide.

Figure 9 is a front elevation of the matrix holder.

Figure 10. is a partial side elevation of the matrix plate.

Figure 11 is an enlarged transverse. section through the mold.

Figure 12 is a detail of the operating lever for the upper backing paper clamps.

Figure13 is a detail view of the operating lever for the lower backing paper clamp.

Figure 14 is a detail view, partly in section, showingthe air cylinder and control pedal.

, Figure 15 is a section taken on, the line |5-l5 of Figure 14.

Figure 16 is a diagrammatic representation of the cooling and heating system; and

Figure17 is a section taken on the line l1-l1 of Figure 6, showing the spring-locking handle.

In the various figures like parts have been indicated by like reference numerals.

In the following description and in the claims, various details will be identified by specific names for convenience, but they are intended to be as generic in theirapplication as the art will permit. Referring to the. embodiment of the invention shown'in 'the drawings, the casting machine is illustratedas comprising a hollow pedestal 28 (Figure 1). which may comprise a base 2| with upstanding sides 22, preferably cast integrally therewith, and having a cover 23 secured thereto, as by bolts ,24,.to provide an air-tight chamber 25 adapted to constitute a compressed air reservoir. A pressure gage 23 may be associated therewith, if desired, to indicate the air pressure within said reservoir. The cover 23 may have webs 26, 21 integrally cast therewithv (Figures 1 and 4) to form the main support for the mold or casting box 28. The mold 28 comprises a backing member or slide 30 (Figures 4-8, 11) and a hinged matrix holder 3| comprising a frame 32 and a matrix plate 33.

The slide 30 may be provided with lugs 34 (Figures 4 and 6) which may becast integrally therewith and may slidably engage guides 35 which are adjustably mounted on the webs 26, 21, as by bolts .36, extending preferably through enlargedholes in said webs to permit transverse adjustment of said guides. Such adjustment may be effected by means of adjusting bolts 31 bearing against said guides 35 and carried in lugs36 formed on the webs 26, 21.

The frame 32 may be hinged by arms 39 (Figures 2 and 4) to a pin 40 which is carried in ears 4! supported by the web 21. The matrix plate 33 may be pivotally mounted, as by a pin 42, on an arm 43, likewise carried by the pin 40.

The frame 32 and the matrix plate 33 may be clamped together by means of a rod 244 pivoted, as by a pin 245, to ears 246 which may be carried by the frame 32. The rod 244 engages a slot 252 (Figure 6) formed in the free end of the arm 43 and is secured by a split clamp 25!) having an operating handle 25L The split clamp 250 may be locked by a bolt 254 in position on a bushing 253 which may be threaded on the rod 244.

The matrix holder 3| may be held against the slide 36 to close the mold 28 by a rod 44 which may be pivoted, as by a pin 45, to ears 46 formed on the web .26. The rod 44 mayengage a slot 52 (Figure 2) formed in the free end of the arm 43. The slot 52 may be formed as an enlargement of the slot 252, the rod 244 being sufficiently small to enter the slot 252, whereas the rod 44 is adapted to seat in the slot 52.

The rod 44 is locked in place in the slot 52 by a split clamp 5|] clamped on a bushing5l which.

is threaded on'the rod 44. The split clamp is adapted to bear against a sleeve 260, which is loosely journalled on the bushing 51. The split clamp 5|] carries a lug 26! (Figures 1 and 17) against which a plunger 262 bears. The plunger 262 is slidably journalled in a handle 263 and is held against the lug 26I by a spring 264, the tension of which may be adjusted by a threaded plug 265. The handle 263 is carried in an ear 266 formed on the sleeve 268., 'The relative motion between the sleeve 260 and the split clamp 50 may be limited by a lug 261 (Figure 4) formed on the split clamp 50 and cooperating with a slot 268 formed in the sleeve 260.

A flange 55 may be carried by the web 26 in a position to engage the frame 32 to act as a stop for determining the closed position of the matrix holder 3| and to prevent the holder from exerting sufficient pressure upon the slide 38 to interfere with the operation thereof.

The frame 32 may carry an arm 51 (Figures 2, 4 and '7) adapted to engage a latch 58 to lock the frame and matrix plate in open position. The latch 58 may be pivoted to one of the ears 4|, of the web 21, as by a pin 59, and may be held in cooperative position with respect to the arm 51 by a spring 60. released when the mold 28 is to be closed. "The mold 28 is mounted at a slight inclination to the vertical, for example 5, so that the molten metal flows down the slide 36, generally out of contact 7 with the matrix on the matrix holder 3 I, thereby protecting the matrix from injury or distortion due to contact with the stream of hotmetal.

The slide 30 (Figures 5-8, and 11) is formed with a plane surface 6| constituting the back of the mold cavity, and with a surface 62, offset with respect to the surface 6|, and connected thereto by a sloping surface 63 which is adapted to guide the metal to the mold cavity during the pouring operation. A cover plate 65 may be secured to a bead 66 (Figures 3, 5-7, and 11) formed on the back of the slide 30, as by bolts 61, to form a chamber 10 adapted to receive compressed air for the purpose to be described. A plurality of transverse bores 11 are formed in'the slide 30 and extend from the chamber 10 to the surface 61 of said slide, Certain of said bores may be The latch 58 may be manually inclined to the transverse axis of the machine so that a greater separation is effected at the surface 6| than at the chamber I0, thereby distributing the air from the chamber 10 over a greater area of said surface for the purpose to be described.

The cover plate 65 also carries a lug 59 adapted to receive a rod I2. which may be secured by positioning nuts I3, and may be connected to a suitable piston 1 (Figures 4 and 5), by which vertical movement of the slide 30 is effected. The lug 59 may also be provided with a transverse port I5, communicating with the chamber I0, and adapted to receive a pipe I6 through which compressed air is supplied.

The slide 36 may be provided with a plurality of transverse bores TI (Figures 5-8, 11) communicating with side channels 80 in which strips 8| are secured. These strips are recessed to join alternate sets of bores to form a coiled duct I8, the ends of which may be connected with flexible pipes '55. as (Figures 3, 4) through which a cooling fluid, such as water, may be circulated to maintain the slide at a desired casting temperature. Obviously, a coiled pipe may be cast directly into the slide, if desired, or the cooling water may be circulated by other means so as to obtain an efficient heat transfer relationship.

During the casting operation, the slide 30 is adapted to be covered with backing paper 85, such as a heavy calendered paper (Figures 5, 3 and 11). For securing this paper in place, a pair of upper clamps B6 and a lower clamp 81 are provided. The clamps 86 are adapted to rest upon the surface 62 of the slide 30 and extend toa point adjacent the sloping surface 63 thereof. Said clamps 86 may be provided with hub portions 83 offset laterally to afford clearance for the backing paper 85. and keyed to a shaft 90 (Figures 5, 5i and 12). which is carried in suitable supports BI formed on the slide 30. For operating the clamps 35. a lever 92 is provided, having a handle 93, and pivoted at one end, as at 94, to a link 95. The link 95 is pivoted at 95 to 2. lug 91 formed as a part of the slide 30. An arm 98" is keyed to the shaft 95 and is pivoted, as at 99, to the lever 92. The arrangement is such that the lever 92 and the link 95 constitute a toggle joint which, in the position illustrated in full lines in Figure 12. holds the clamps 85 securely against the backing paper 85. When the lever 92 is moved to the position illustrated in dotted lines in Figure 12, the toggle is broken and piovtal movement of the arm 98 causes the shaft 90 to rotate and thereby to swing the clamps 85 away from. the backing paper for releasing the same.

The lower clamp 8'! is carried by a support I (Figures 5, 8 and 13) which is journalled between spaced bearing blocks IUI secured to the bottom of the slide 35 by bolts I92. The support I00 may have an arm I0! associated therewith and pivoted at H35 to an adjustable link I08, which, in turn, is pivoted at I09 to a lever III! having a handle H2. The lever III] is pivoted at II3 to cars I It carried by the slide 30. When the lever MI) is in vertical position, as illustrated in full 1 .1195 in Figure 13, thelower clamp 81 is held securely against the backing paper 85 on the surface 6! of the slide 30, but when the lever I I0 is in the position shown in dotted lines in Figure 13, the link IE8 is elevated, thereby swinging the clamp Bl away from the surface GI and releasing the backing paper 85 therefrom.

IIB (Figures -7, 9 and 11) adapted to form a liquid-tight seal with the surface 6| of the slide 30 or with the backing paper 85 which may be positioned thereon. The bottom flange IIImay have a recess I I9 to slidably receive the lower clamp 87 and to effect a seal therewith. The bottom flange II'I may be formed on a separate member 219 made, for example, of steel so as to provide greater strength. The member 210 maybe secured to the frame 32 by bolts 2II (Figure 5). Positioning dowels 2I2 may be provided for helping to support the member 210 in the proper position. The flanges I I6, I I1 and I I8 form the sides of the mold and define the peripheral edges of the cast stereotype plate. The clamp 81 constitutes a plunger to apply pressure to the molten metal in the mold cavity. The flange H8 is spaced from the surface 62 to provide a passage I I50 terminating in a flared opening 'I5I through which the molten metal may be poured when the slide is in its lower position. When the slide is raised, the surface 6| cooperates with the flange I I8 to nearly close said passage and to confine the molten metal under the pressure applied by said clamp 81, or by compressed air to the back of the backing paper. This clamp 87 may be made comparatively thin so as to form only a portion of the bottom of the mold cavity or, in some cases, may be positioned below and outside of the mold cavity. In the latter case, movement of the slide 30 closes, or substantially closes, the passage I50 so as to confine the molten metal in the mold cavity and pressure is supplied by the compressed air on the backing paper to produce a casting having the desired characteristics.

The frame 32 may be provided with upper knock-out plungers I52 seated, for example, in transverse recesses I53 in said frame (Figures 5 and. 9), and having racks E54 engaging a gear I55 which is carried on a shaft I56 (Figures 1-5) journalled in said frame and having an operating handle I51 keyed thereto. When the plungers I52 are retracted, molten metalv may enter the recesses I53 in front of the plungers I52 and form slugs which cause the solidified riser or gate between the flange IIS and the surface 62 to adhere to the flange IIB when the mold. is opened. When the handle I5! is rotated, the knock-out plungers I52 push the slugs out of the recesses !53 and release the solidified riserfrom the flange H8.

A set of lower knock-out plungers 215 (Figures 5 and 9) may be held in transverse recesses 216 in the frame 32. The plungers 215 may have racks 211 engaging a gear 218 formed on or carried by a shaft 2% which is journalled in the frame 32 and has an operating handle 280. A spring 28! may be seated around each plunger 215 between a bushing 282 carried by the plunger and the surface of the frame 32.

The plungers 215 may have clips 283 formed thereon or secured thereto. Said clips may have vertical parts 234 adapted to seat in recesses 285 (Figure 9) formed in the member 210 and forming with said member 275 a substantially continuous surface when the plungers 215 are retracted. The clips 283 may also have rear horizontal flanges 285 which are adapted. to close the recesses 27% when the plungers 215 are operated. The vertical parts 284 of the clips 283 may terminate in. inclined surfaces 287 which engage corresponding lugs cast on the bottom of the stereotype plate for pushing the same from the matrix when the plate is to be removed.

The frame 32 may also be provided with a pluof said plate.

rality of upper horizontal bores I2I adapted to receive electrical heating rods I03 of any standard type which may terminate in side channels I22,.closed, if desired, by a cover plate I23. The

5 frame 32 may also be provided with lower horizontal bores I24 adapted to receive similar heating rods I04, terminating in side channels I25 covered, if desired, by a cover plate I26.

The matrix plate 33 may have transverse bores I30 formed therein terminating in side channels I3I in which strips I32 are secured. These strips are recessed to connect alternate sets of bores I30 to form a coiled duct I34 (Figures 2, 5, 6, 9 and 11), having terminals connected to flexible l5 pipes I38, I39 through which a cooling fluid,

such as water, may be circulated. The duct I34 is shown as'an example only. Other positive cooling means may be employed if desired.

Said matrix plate 33 may be provided with a 0 pair of side clampsl40 secured to the edges thereof, as by screws I4I, extending through elongated slots I42 (Figures 10 and 11) formed in said side clamps to permit transverse movement thereof with'respect to the matrix plate.

25 Said clamps I40 may be provided with flanges I43 which are adapted to seat in grooves I44 formed at the'two side edges of the matrix plate for gripping the edges of the matrix. Spring fingers I46 may be formed at the bottom of the 30 flanges I43 to hold the lower edge of the matrix while the moldis in open position.

The pressure of the side flanges H6 on the clamps I40, as the matrix plate 33 is closed against the frame 32, causes the flanges I43 to engage a matrix I45 and to pull the side edges into the grooves I44, thereby pulling the matrix tightly against the matrix plate 33. When the mold is in closed position, the matrix is held against the flanges I I6, I I1 and I I8 of the frame 40 32 which may extend substantially around the periphery 'of the matrix and securely clamp the marginal edges thereof so as to prevent subsequent movement, due, for example, to shrinkage of the matrix or to the shrinkage of the cast 45 plate.

55 matrix against the matrix plate.

Pivotal adjustment of the matrix plate 33 is obtained by means of pads I62 (Figures 6 and 7), carried on said plate 33, and engaging adjustable bolts I63 carried on the arm 43, the

"(i0 adjustment being such. as to permit a slight pivotal movement of the matrix plate about the pin 42 so that the plate may firmly seat against the flanges H6, H1 and H8 of the frame 32 when the mold is in closed position.

: 0 For operating the slide there is provided a housing I64 having a cylinder I65 therein (Figures 1, 2, 5, 14 and in which the piston 14v is seated. A bumper 14a, comprising a ring of resilient material, such as rubber, may be lo- '7 0 cated above the piston 14 in the cylinder I65 so as to engage the cap I66 to limit the movement of the piston when compressed air is applied thereto.

The housing I64 may be carried on the pedestal 1,75 and may be provided with a cap I66 through which the shaft 12 extends. The cylinderI65 communicates through a bore I61 with the air reservoir and is provided with a valve mechanism comprising a housing I68 and a valve I69 adapted to seat thereon for controlling the flow of air from the reservoir to the cylinder. The valve I69 may be mounted on a stem I10 and normally held in closed position by a spring I1I. For releasing the same, a foot lever I12 is provided having an abutment I13 adapted to bear against an adjustable bolt I14 carried by the abutment I13.

The lever I12- may be formedwith a hub I15 which may be-pivoted, as by a pin I16, between ears I11 formed on the housing I64. The lever I12 is also provided with a shoulder I80 which is adapted to engage the base 2| to limit the downward movement of the lever.

For locking the lever I12 in its lower position, there is provided a link I82having a shoulder I 83 adapted to engage an abutment I84 formed ona plate I85 which may be'secured to the housing I64 in any convenient manner. The link I82 may slidably engage a screw I86 and may be pivotally connected, as at I81, to one web I88 of a foot pedal I89, having a rear edge I90 and a front edge I9I. The foot pedal I89 is provided with a pair of webs I88, which extend on opposite sides of thelever I12, and are pivoted thereto, as by a pin I93.

The arrangement is such that pressure on the front edge I9I of the foot pedal I89 depresses the lever I12 and causes the link I82 to. lock against the abutment I84, as illustrated in Figure 14, thereby opening the valve I69 and holding the same in open position. Pressure on the rear edge I90 of the pedal I89 causes pivotal movement of the pedal about the pin I93, thereby withdrawing the link I82from engagement with the abutment I84 and permitting the valve I69 to be closed by the action of the spring I1 I.

The cylinderI65 is closed at the top whereby upward movement of the piston compresses the air trapped within the upper part of the cylinder and forms a cushion which assists the bumper 14a .in retarding the movement of the piston and the associated mechanism.

A port I96 may be located in the housing I64 in a'positionto be uncovered. when the piston has neared the end of its normal operating stroke.v This port I96 is connected, through a pressu'rereduction valve I91 and agage I98, to the pipe 15 by which air is applied to the chamber 10 at the back of the slide 30.

The matrix plate 33 may be provided with a boss I99 (Figures 2 and 6) having a well200 rearwardly inclined. to receive a thermometer 20 I- and with awell 202 adapted to receive the bulb 203 of a thermal-responsive device 204. A boss 205 may be formed on the slide (Figure 3) having wells 206, 201 to receive a thermometer 208 and the bulb 209 of a thermal-responsive device 2I0 respectively.

The thermal-responsive devices 204 and 2I0 may constitute make and break relays operated by an expansible-fluid contained in the bulbs 203 and 209 in response to temperature variations in the matrix plate 33 and in the slide 30 respectively. They may be supported on the apparatus in any convenient position and may be connected to a supply main 2II (Figure 16) to control the current to solenoid valves 2I2, 2I3 respectively, which are connected in the pipes I 38 and 19 to control the flow of cooling water through the ducts I34 and 18 respectively. The valves 2I2,

2l3 may be connected to a supply line 2I4 and the flexible pipes 84 and I39 may be connected to a discharge line H5. The thermal-responsive relays 264, 216 and the valves 2l2, 213 may be of any standard type adapted to admit cooling water at a given maximum temperature and to interrupt the flow of cooling water at a given minimum temperature. A signal light 2l 6 may be connected in parallel with the solenoid valve 2l2 so as to indicate when the temperature conditions of the matrix plate are such as to require cooling water, in which case the temperature is too high for pouring.

-The valves 2l2, 253 may be supported by the pedestal 26 in any convenient position. Suitable connections are also made from main 2 to the heating rods I03, I64 so that these rods are energized whenever the main switch (not shown) is closed.

In the operation of this device, the backing paper 65, which preferably comprises a sheet of strong craft paper, is inserted under the clamps 86 and between the hub portions 83 thereof, and is extended downwardly under the lower clamp 87, the clamps 86 and 81 being released by suitable operation of the levers 92 and H6 for this purpose. Thereafter, said levers are operated to cause the clamps 86 and 81 to engage the backing paper and to securely hold the same in positlon. The clamps 86 are adapted to cause the paper to bend over the inclined surface 63 of the slide 36 and are of such thickness that the face of the clamps 86 and the face of the backing paper over the surface 6| lie in substantially the sameplane. If the lower clamp 81 is positioned outside of the mold cavity as, for example, below the slide, the backing paper is extended accordingly. In some instances the lower clamp 81 may be omitted and the backing paper allowed to hang free or to be held by the bottom flange H! of the frame 32.

. The matrix is applied to the matrix plate 33, preferably while at a high temperature, when the mold is open, as in Figure '7, and is temporarily held by the clamping strips I46. The matrix' plate 33, with the matrix in position thereon. is then swung into closed position against the frame 32. When the matrix plate 33 comes in contact with the flanges l 46 of the frame, pressure is exerted which causes the clamps 1 .6 to retract and to pull the edges of the matrix into the grooves I44 of the matrix plate. Thereafter, the flanges 1 !6, H! and I I8 of the frame 32 clamp the edges of the matrix and prevent movement thereof, due to expansion and contraction on repeated use which would tend to buckle the matrix after a few plates had been cast,

The frame 32 and the matrix plate 33 are locked together by means of the rod 244 and the lock nut 256, the lock nut being tightened by the handle 25!. sufiiciently to hold the frame 32 firmly against the stationary flange 56.

The matrix holder 3i is closed against the flange 55 and is locked by the rod 44 and split clamp 56. It is to be noted that the pressure is limited by the spring 264. As the handle 263 is turned, the plunger 262 bears against the lug 26l of the split clamp 50 and turns the split clamp 56 to clamp the matrix holder against the flange 56 until the force becomes sufiicient to compress the spring 264. The operator thus feels the handle give and knows that the matrix holder is sufficiently tightened. This arrangement prevents a force being applied which would spring the parts or break the thin flanges H6, H1 and The slide 30, when properly positioned with respect to the frame 32 by means of suitable adjustment of the bolts 37, is locked in its position by tightening the bolts 36. This adjustment is such that the side and bottom flanges I I6 andl ll of the frame 32 effect a liquid-tight seal with the backing paper carried upon the slide 30 and with the clamp 81. The backing paper is preferably permitted to extend a substantial distance above the slide 36 so as to protect the top of the slide and the associated mechanism from the molten metal during the pouring operation.

With the parts thus assembled, the heating rods H13, I64 are energized to prevefit the metal in the passage 156 and the metal around the clamp 31 from solidifying until the plate has been cast and the desired pressure applied thereto. The cooling water is automatically supplied to the ducts 78 and I34, if the temperature of the slide and of the matrix plate exacts the predetermined value.

If, for example, a type metal is to be used having a pouring temperature of 550 F. and a freezing temperature of 475 F., the machine is preferably maintained at a temperature of about 120 F. The thermalresponsive devices 204, m may be adjusted to maintain the mold at about this selected temperature. If the machine is cold, as in the morning, one or more dummy plates may be cast to bring it up to the proper temperature. Thereafter, the temperature is controlled by the heating rods and by the cooling coils to maintain the desired casting conditions.

The molten metal is preferably maintained at a predetermined temperature which is most suitable for pouring purposes, such, for example, as a temperature of 550 F. as above mentioned. With the temperature of the metal before pouring and thetemperature of the machine both constant, the plates are cast under uniform conditions and hence the cooling period, shrinkage, and other characteristics of the various plates are substantially the same.

With the machine at the required temperature, the metal is poured into the flared opening I51 and passes downwardly over the surface 62 of the slide, is deflected by the inclined surface 63, and thence falls over the surface 6! until the mold cavity gradually becomes full of molten metal. It is to be noted that the backward inclination of the machine causes the metal to flow downwardly over the backing plate instead of over the matrix, thereby preventing injury to the matrix impressions and preventing unequal heating or expansion of the matrix. As the metal gradually fills the mold cavity, any air which is caught between the back of the matrix and the matrix plate 33 gradually rises to the top where it is released through the apertures I66, thereby permitting the matrix to lie flat against the matrix plate. The matrix and the backing paper act as partial heat insulators to prevent the metal from being immediately chilled by contact with the metal parts of the mold. The backing paper also retards the cooling of the metal sufficiently to prevent the metal from solidifying before actuation of the slide 30 and interfering with the operation thereof.

The pouring is preferably continued until the molten metal fills the entire mold cavity and rises along the surface 62 to a point adjacent the flared opening l5l. Thereafter, the foot pedal I89 is depressed, opening the valve I69 and allowing air from the reservoir 25 to enter the cylinder I65 and raise the piston 14. This causes an upward movement of the slide during which the clamp 81 operates as a plunger, agitates the metal, and forces the same upwardly and out through the aperture between the inclined surface 63 of the slide and the top flange III! of the frame 32. Continued movement of the slide 30 causes the surface 6| to register with the face of the flange H8 and thereby substantially close the opening of the mold cavity. Thereafter, further movement of the slide compresses the molten metal within the mold cavity and causes the same to penetrate the impressions in the matrix.

This movement continues until the piston is stopped by the bumper blocks 14a or until the pressure exerted by the molten metal balances the pressure applied to the piston I4. The sudden movement of the slide 30 produces an impact effect which greatly increases the pressure exerted upon the type metal.

The arrangement is such that, just before the piston I4 reaches the limit of its movement, the port I96 is uncovered and permits the air from the cylinder I 65 to be applied through the pipe I6 and pressure reductionvalve I91 to the chamber and thence through the bores H to the back of the backing paper 85. This air pressure serves to force the backing paper away from the slide, exerting pressure on the back of the casting to hold the printing face firmly against the matrix as the metal shrinks while cooling. The pressure-reduction valve I91 reduces the air pressure to a value such that the desired effect is obtained. Obviously, this valve may be omitted if the air in the cylinder is at the proper pres sure for the above purpose.

The heating rods I03 and I04 maintain the metal in molten position at the constricted points of the mold until the casting has been completed. Obviously, the clamp 81 and the passage I50 must be free if the proper operation is to be obtained. The cooling ducts l8 and I34 remove heat from the mold at the large flat surfaces of the casting, hasten solidification and prevent the mold from reaching too high a temperature due to continued casting operations. The controlled flow of cooling water in positive channels from the top to the bottom of the respective surfaces ensures a uniform, controlled cooling effect.

Inasmuch as the matrix is firmly clamped around its periphery by the flanges II6, II"! and H8, it is held under tension or in a stretched condition due to any shrinkage which may have taken place upon cooling from its original high temperature. The pressure which is maintained on the face of the matrix by means of the slide 30 and by the air applied to the backing paper 85 assists in holding the matrix fiat against the matrix plate 33, whereby bulging or wrinkling, due to reheating by the hot metal, is prevented. Hence, the cast plate will correspond exactly in size and registration to the original impressions on the matrix.

If the pedal I89 is accidentally depressed when the mold is not filled with molten metal, the closed space at the top of the cylinder I65 acts as an air cushion to stop the piston and the slide without injury to the apparatus.

When the metal has cooled below its solidiflcation temperature and while it is still at an elevated temperature, such as 120 F., the cast stereotype plate is removed from the machine and further cooling is effected in any convenient manner, using precautions to prevent buckling of the plate.

For removing the plate from the machine, the air pressure is released from the cylinder I85 by applying pressure to the rear edge I 90 of the foot pedal I89, thereby withdrawing the link I 82 from the abutment I84 and permitting the valve I69 to close. The Weight of the slide then causes the piston I4 to return gradually to its lower position as the air leaks around the edges of the piston. The split clamp 50 may then be loosened by suitable manipulation of the handle 263 to permit the rod 44 to be swung away from the arm 43, whereupon the matrix holder 3| may be swung into open position. During this operation the stereotype plate will adhere to the matrix and will accordingly be released from the backing paper and will follow the frame32 and the matrix plate 33 asthe same are swung into open position. 1'

The handle 280 is now actuated to cause the lower knockout plungers 215 and the clips 283 to push the bottom of the plate from the frame 32. Theplate may be grasped and torn from the thin riser or gate which has solidified opposite the flange II 8 of the frame 32 and may be re-i moved'and cooled in any convenient manner."

The gate between the flange H8 and the surface 62 of the slide 30 may include lugs formed by metal which has entered the recesses I53 and has solidified therein. These lugs cause the gate to adhere to the flange II8 of the frame 32 when the frame is opened. The gate may be removed therefrom by manipulating the handle I51 to cause the plungers I52'to push said lugs from the recesses I53 and may be remelted and used for further casting operations.

The matrix plate 33 remains locked by the rod 244 against the frame 32. Hence, the matrix remains firmly clamped therein and shrinkage or distortion 'due to the molten metal is prevented. A plurality of successive plates may thus be cast which are exact duplicates as to size and registration. This is particularly important for color printing Where exact registration is essential.

When the matrix is to be removed, the handle I is actuated to release the rod 244 and to permit the rod to swing out of the slots 52 and 252 5 of the arm 43.

It is contemplated that the same backing pape may be used for several casting operations. If further plates are to be cast, the machine may be reclosed and the above operation repeated. It is to be noted that the cooling ducts maintain the machine at the required temperature by removing the heat of casting. Consequently, if the molten metal is always poured at a predetermined temperature, uniform results can be obtained.

Although the above machine may be used with any type of matrix, it is particularly adapted for use with the matrix described in my copending applications Serial No. 714,916, filed March 10, 1934, for Matrix and method and apparatus for making the same, and Serial No. 752,037, flled November 8, 1934, for Stereotype matrix and production thereof. The matrix therein described is treated to obtain a uniform back surface from which all irregularities have been re moved, for example, by grinding the surface while the matrix is still held in position on the type form. In this way the matrix is so formed that, when it is placed on the smooth surface of the matrix plate, the various impressions retain their original relative position and the stereotype plate cast therefrom in the above-described manner accurately reproduces the original form from which the matrix was impressed.

When used in this manner, the stereotype plate is ready for mounting as soon as the back is planed to the desired thickness. The printing face is accurate because the matrix is accurately formed to eliminate all irregularities therefrom, the matrix is held against a flat surface in the mold, the matrix is prevented from bulging or distorting, the plate is held in engagement with the matrix while cooling and solidifying, and the casting operation is carried out at predetermined temperatures. The process accordingly reduces the manipulative steps to a minimum, renders manual correction of the plate unnecessary, and produces a cast stereotype plate at low cost having characteristics suitable for high quality printing.

t is to be understood that the present invention is equally applicable to the casting of curved or flat stereotype plates. A machine for producing flat plates has been illustrated by way of example only and not as a limitation of the invention.

Although a particular embodiment of the invention has been shown and described for purposes of illustration, it is to be understood that various changes and modifications may be made therein by a person skilled in the art without departing from the scope of the invention which is only to be limited in accordance with the following claims when interpreted in view of the prior art.

I claim: 7

1. A machine for casting stereotype plates comprising a mold having a mold cavity adapted to receive a matrix against which the stereotype plate is to be cast, and a passage leading thereto through which molten metal is poured, means to close said passage, means to apply pressure to the molten metal to compress the same within the mold cavity and to force the metal into the impressions in the matrix, and yieldable means to distribute pressure over substantially the entire back of the cast stereotype plate to compensate for shrinkage and to hold the plate in pressure engagement with the matrix until and after solidification takes place.

2. A machine for casting stereotype plates comprising a mold adapted to receive a matrix against which the metal is to be poured, means to exert pressure against the molten metal in said mold and cause the same to penetrate the impressions in said matrix, and means operable while said metal solidifies to exert pressure against the back of the stereotype plate to compensate for shrinkage and to maintain the face thereof in registra-v tion with said matrix.

3. A machine for casting stereotype plates comprising a mold having a mold cavity adapted to receive a matrix against which the stereotype plate is to be cast, and a passage leading thereto through whch molten metal is poured, said mold having a slidable backing member forming the back of the mold cavity, and means whereby sliding movement of said backing member causes said backing to first close said passage and then to apply pressure to the molten metal therein to compress the same and to force the metal into the impressions in the matrix.

4. A machine for casting stereotype plates comprising a mold having a mold cavity adapted to receive a matrix against which the stereotype plate is to be cast, and a passage leading thereto through which molten metal is poured, said mold having a slidable backing member forming the back of the mold cavity, said backing member having a plunger associated therewith to form at least a portion of the bottom of the mold cavity, and means whereby sliding movement of said backing member first closes said passage and then causes said plunger to apply pressure to the molten metal Within said cavity.

5. In a machine for casting stereotype plates, a mold having a mold cavity adapted to receive a matrix against which the stereotype plate is to be cast, a flexible backing member adapted to form the back of said mold cavity, means to substantially close the mold cavity, and means to apply fluid pressure to the back of said flexible backing member to cause said backing member to exert pressure on the cast stereotype plate to compensate for shrinkage of the metal on cooling and to maintain the face of the stereotype plate in pressure engagement with said matrix.

6. In a machine for casting stereotype plates, a mold having a mold cavity adapted to receive a matrix against which the stereotype plate is to be cast, a member forming the back of said mold cavity, a flexible backing mounted on said member, said member having air ducts to distribute air under pressure to said backing, whereby said backing is caused to exert pressure on the cast stereotype plate to compensate for shrinkage of the metal while cooling and to maintain the face of the stereotype plate in pressure engagement with the matrix.

7. In a machine for casting stereotype plates, a mold having a mold cavity, a slide forming the back of the mold cavity, means to clamp the backing member thereto comprising a clamp extending substantially across the bottom of said slide and at the bottom of the mold cavity, said clamp being adapted to constitute a plunger to exert pressure on the molten metal in said cavity in response to movement of said slide.

8. In a machine for casting stereotype plates, a mold having a mold cavity, a slide adapted to constitute the back and at least a portion of the bottom of said mold cavity, means to operate said slide comprising an air cylinder and a piston,

means to apply air under pressure to one end of said cylinder for causing movement of said piston, the other end of said cylinder being closed and adapted to provide an air cushion to limit the movement of said piston and the slide associated therewith. V

9. In a machine for casting stereotype plates, a hollow pedestal adapted to constitute a reservoir for compressed air, a mold carried thereby having a plunger adapted to exert mechanical pressure on the molten metal therein, a compressed air cylinder associated with said plunger for operating the same, and a valve to control the passage of air from said reservoir to said cylinder.

10. In a machine for casting stereotype plates, a mold having a mold cavity, a slide adapted to constitute the back and at least a portion of the bottom of said mold cavity, means to operate said slide comprising an air cylinder and a piston, a compressed air receiver, a valve adapted to control the passage of air from said receiver to said cylinder, and means to operate said valve comprising a pedal pivoted for movement in response to pressure on the front and rear edges respectively thereof, a link adapted to lock said valve in open position, said link being releasable in response to pivotal movement of said pedal.

11. In a machine for casting stereotype plates, a mold having a mold cavity adapted to receive a matrix against which the stereotype plate is to be cast, and a passage leading thereto through which molten metal is poured, a slide carrying,

. response to operation thereof, a port formed in said cylinder in a position to be uncovered by said piston as the piston nears the end of its stroke, fluid passages in said slide arranged to apply fluid pressure to the back of said backing member, and means connecting said passages to said port whereby said fluid pressure is applied subsequent to the application of pressure to the molten metal by movement of said piston.

12. In a machine for casting stereotype plates, a mold including a matrix holder comprising a matrix plate having clips adapted to secure a matrix thereto, and a unitary frame having marginal flanges extending around the entire mar ginal periphery of said matrix, said flanges being adapted to clamp the matrix against said plate and to define the marginal edges of the cast stereotype plate.

13. In a machine for casting stereotype plates, a mold comprising a mold cavity and a passage leading thereto through which metal is poured, a matrix holder adapted to hold the matrix in position to form the front of said matrix cavity, said matrix holder having recesses communicating with said passage and adapted to form slugs on the gate which solidifies in said passage,

whereby said gate is held on said matrix holder when the mold is open, and plungers seated in said recesses and adapted to engage said slugs to release the gate from said matrix holder.

14. In a machine for casting stereotype plates, a mold comprising a mold cavity and a passage leading thereto through which metal is poured, a matrix holder adapted to hold the matrix in position to form the front of said matrix cavity, said matrix holder having recesses communicating with said passage and adapted to form slugs on the gate which solidifies in said passage, whereby said gate is held on said matrix holder when the mold is open, plungers seated in said recesses and adapted to engage said slugs to release the gate from said matrix holder, an operating handle, and means mechanically interconnecting said handle and said plungers for controlling the oper-- ation thereof. 7

15. In a machine for casting stereotype plates, a mold having a mold cavity, a matrix plate adapted to hold the matrix in position to form the front of said cavity, a unitary frame adapted to form the four edges of said cavity and to clamp the matrix to said matrix plate, a pivoted arm, and means pivotally securing said matrix plate to said arm whereby said matrix plate is adapted to swing against and seat on said frame to clamp the matrix therebetween when said plate is brought into closed position. 7

16. In a machine for casting stereotype plates, a mold comprising a slidable backing member and a hinged matrix holder adapted to form the front and back respectively of the mold cavity, means supporting said slidable member and said matrix holder, means to clamp said matrix holder in closed position, a stop associated with said supporting means, said matrix holder being adapted to engage said stop to prevent the pressure of said clamping means from being transmitted to said slidable member, and means to adjust said slide with respect to said hinged matrix holder so as to effect a substantially fluid-tight seal therebetween.

17. In a machine for casting stereotype plates, a mold comprising a matrix plate adapted to support a matrix against which the stereotype plate is to be cast, a frame adapted to engage the peripheral edges of said matrix and form the edges of the mold cavity, said frame having transverse bores upon and below the matrix plate, and electrical heating rods located in said bores.

18. In a machine for casting stereotype plates, a mold comprising a slidable backing member and a hinged matrix holder adapted to form the front and back respectively of the mold cavity, means supporting said slidable member and said matrix holder, means to clamp said matrix holder in closed position, said clamping means comprising a rod carrying a threaded clamping member, an operating handle for turning said member, and spring means to limit the force exerted by said handle on said member.

19. In a machine for casting stereotype plates, a mold having a mold cavity, a slide adapted to constitute the back and bottom of said mold cavity, means to operate said slide comprising an air cylinder and a piston, means to apply air under pressure to one end of said cylinder for causing movement of said piston, and a stop comprising a resilient member in said cylinder above the piston to limit the movement thereof.

GEORGE W. BUNGAY. 

